Pipe machining apparatus

ABSTRACT

In a pipe machining apparatus A, a region of a part including a first pressure contact part 61a which comes into pressure contact with a first portion 11a of a pipe P in a lower clamper part 6 of a clamping device C serves as a first movable clamper part 61 which is separate from a different region 63 of the lower clamper part 6, and the pipe machining apparatus A includes a first displacement member 8A that is able to displace the first movable clamper part 61 in a predetermined first direction D1 after machining of the pipe P ends. According to such a constitution, a pipe machining apparatus capable of appropriately resolving aggravation of workability of removing a pipe caused by a part of the pipe which comes into pressure contact with a lower clamper part of a clamping device can be provided.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of Japan Patent Application No. 2021-212840, filed on Dec. 27, 2021. The entirety of each of the above-mentioned patent application is hereby incorporated by reference herein and made a part of the specification.

BACKGROUND Technical Field

The disclosure relates to a pipe machining apparatus used for machining such as pipe expansion or pipe contraction of an end part of a pipe.

Description of the Related Art

Patent Documents 1 and 2 disclose specific examples of a pipe machining apparatus. The pipe machining apparatuses disclosed in these documents include a clamping device that clamps a pipe which is a machining target, and a machining part for performing machining using a machining tool with respect to an end part of the pipe in a state in which the pipe is clamped. The clamping device includes an upper clamper part and a lower clamper part. In the machining part, a machining tool such as a punch for pipe expansion or for flange forming approaches and abuts the end part of the pipe from a lateral side thereof.

In such a pipe machining apparatus described above, an upper clamper part and a lower clamper part constituting a clamping device may also serve as a die forming a pair with the machining tool. In such a case, a phenomenon in which a part of a pipe comes into pressure contact with any of the upper clamper part and the lower clamper part is likely to occur due to a pressure during machining of an end part of the pipe by the machining tool. Regarding a specific example, as an example of pipe machining, there is a step of forming an annular projection part protruding outward in a radial direction in an outer circumferential wall of a pipe. When this step is performed, in a portion corresponding to the annular projection part in the upper clamper part and the lower clamper part, a phenomenon in which the annular projection part comes into pressure contact therewith with a considerably strong force in an axial length direction of the pipe may occur.

When the foregoing phenomenon occurs, there is a probability that a pipe will not be able to be simply detached with a relatively weak force when the pipe is removed from the clamping device after machining of the pipe ends. Since such a probability may lead to aggravation of workability of removing a pipe which has been machined, it may cause a delay in work of setting a next new pipe in the clamping device and eventually may cause degradation in efficiency of pipe machining work. Therefore, it is desirable to appropriately resolve such a problem.

PATENT DOCUMENT

[Patent Document 1] Japanese Patent Laid-Open No. 2017-170509

[Patent Document 2] Japanese Patent Laid-Open No. 2017-170510

[Patent Document 3] Japanese Unexamined Utility Model Application No. H5-227

SUMMARY

The disclosure provides a pipe machining apparatus including a clamping device that has a lower clamper part on which a pipe is placed and an upper clamper part which is positioned above this lower clamper part and able to ascend and descend, and is able to clamp an end part of the pipe between the lower clamper part and the upper clamper part; and a pipe machining part that causes a machining tool to abut the end part of the pipe and performs machining of the end part in a state in which the end part of the pipe is clamped by this clamping device. The lower clamper part is provided with a first pressure contact part which comes into pressure contact with a first portion of the pipe at a time of machining of the pipe and receives a force in a first direction from an outward side toward an inward side in an axial length direction of the pipe from the first portion. A region of a part including the first pressure contact part in the lower clamper part is constituted as a first movable clamper part which is separate from different regions of the lower clamper part. The pipe machining apparatus further includes a first displacement member that is able to displace the first movable clamper part in the first direction after machining of the pipe ends.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross-sectional plan view illustrating an example of a pipe machining apparatus according to the disclosure.

FIG. 2 is a schematic cross-sectional view along II-II in FIG. 1 .

FIG. 3 is a schematic cross-sectional view illustrating an operation state of the pipe machining apparatus illustrated in FIG. 1 from a state illustrated in FIG. 2 .

FIG. 4 is a schematic cross-sectional view along IV-IV in FIG. 1 .

FIGS. 5A to 5C are schematic cross-sectional views schematically illustrating a transfer device provided in the pipe machining apparatus illustrated in FIG. 1 .

FIG. 6A is a cross-sectional view of a main part illustrating a state before machining of a pipe in a pipe machining part S1 of the pipe machining apparatus illustrated in FIG. 1 , FIG. 6B is a cross-sectional view of the main part illustrating a state at the time of machining of the pipe, and FIG. 6C is a cross-sectional view of the main part illustrating a state after machining of the pipe.

FIG. 7 is a cross-sectional view of a main part illustrating a state before machining of the pipe in a pipe machining part S6 of the pipe machining apparatus illustrated in FIG. 1 .

FIG. 8 is a cross-sectional view of a main part illustrating a state at the time of machining of the pipe in the pipe machining part S6 of the pipe machining apparatus illustrated in FIG. 1 .

FIG. 9 is a cross-sectional view of a main part illustrating a state after machining of the pipe in the pipe machining part S6 of the pipe machining apparatus illustrated in FIG. 1 .

FIG. 10 is a cross-sectional view of a main part illustrating a state before machining of the pipe in a pipe machining part S8 of the pipe machining apparatus illustrated in FIG. 1 .

FIG. 11 is a cross-sectional view of a main part illustrating a state at the time of machining of the pipe in the pipe machining part S8 of the pipe machining apparatus illustrated in FIG. 1 .

FIG. 12 is a cross-sectional view of a main part illustrating a state after machining of the pipe in the pipe machining part S8 of the pipe machining apparatus illustrated in FIG. 1 .

FIG. 13 is a cross-sectional view of a joint pipe manufactured by machining using the pipe machining apparatus illustrated in FIG. 1 .

FIGS. 14A to 14I are cross-sectional views of a main part illustrating an example of change in shape of a pipe through machining using the pipe machining apparatus illustrated in FIG. 1 .

DETAILED DESCRIPTION

The disclosure provides a pipe machining apparatus in which a problem of aggravating the work of removing a pipe which has been machined from a clamping device is appropriately prevented or curbed and the efficiency of pipe machining work can be enhanced.

In order to solve the foregoing problems, the disclosure adopts the following technical means.

Preferably, the end part of the pipe is provided with an annular projection part having a partially larger outer diameter than other portions of the pipe. The first movable clamper part has a recessed step part where the annular projection part enters when the pipe is clamped by the clamping device. At the time of machining of the pipe, a stepped part close to a center of the pipe in the axial length direction in the annular projection part is constituted to come into pressure contact with a side wall part of the recessed step part. The stepped part is the first portion, and the side wall part of the recessed step part is the first pressure contact part.

Preferably, the machining tool includes an expansion/contraction deformation part which is able to enter an inner side of the annular projection part and expand the annular projection part at the time of machining of the pipe, and a pressing part which presses the annular projection part in the first direction from the outward side thereof.

Preferably, both end parts including the end part of the pipe and an end part on a side opposite thereto are respectively provided with a pair of annular projection parts as the annular projection part. The lower clamper part has a pair of recessed step parts as the recessed step part where the pair of annular projection parts enter when the pipe is clamped by the clamping device. At least a pair of pipe machining parts which can cause the machining tool to abut both the end parts of the pipe from lateral sides thereof are provided as the pipe machining part.

Preferably, the first displacement member is a first elastic member which elastically biases the first movable clamper part in the first direction at all times. The pipe machining apparatus further includes a first movable clamper part operation part that displaces the first movable clamper part in a second direction opposite to the first direction against an elastic biasing force of the first elastic member such that the first pressure contact part is positioned at a location where the first pressure contact part comes into pressure contact with the first portion at the time of machining of the pipe.

Preferably, the first movable clamper part operation part includes a pushing part which is able to ascend and descend in response to the upper clamper part, and this pushing part is constituted to descend in response to the upper clamper part and abut the first movable clamper part such that the first movable clamper part is pushed in the second direction when the pipe is clamped by the clamping device.

Preferably, the lower clamper part is provided with a second pressure contact part which comes into pressure contact with a second portion positioned on a tip side of the pipe from the first portion in the pipe at the time of machining of the pipe and receives a force in a second direction opposite to the first direction from this second portion. A region of a part including the second pressure contact part in the lower clamper part is constituted as a second movable clamper part which is separate from the different regions of the lower clamper part and the first movable clamper part. The pipe machining apparatus further includes a second displacement member that is able to displace the second movable clamper part in the second direction after machining of the pipe ends.

Preferably, the second displacement member is a second elastic member which elastically biases the second movable clamper part in the second direction at all times.

Preferably, in the pipe machining apparatus according to the disclosure, there is a plurality of pipes as the pipe. The clamping device is able to clamp the plurality of pipes. A plurality of pipe machining parts is provided as the pipe machining part, and machining in which shapes of end parts of the plurality of pipes are changed in stages by the plurality of pipe machining parts is able to be performed. The first movable clamper part is provided in a manner of corresponding to at least one pipe machining part of the plurality of pipe machining parts.

Other features and advantages of the disclosure will become more obvious from the following description of an embodiment of the invention with reference to the accompanying drawings.

Hereinafter, a preferred embodiment of the disclosure will be specifically described with reference to the drawings.

A pipe machining apparatus A illustrated in FIG. 1 is used for manufacturing a joint pipe P8(P) illustrated in FIG. 13 . Prior to description of the pipe machining apparatus A, a constitution of the joint pipe P8 will be simply described below.

The joint pipe P8 includes a joint part 1 at each of both end parts. This joint part 1 includes a folded flat-shaped flange part 10 positioned at a tip of the end part of the joint pipe P8, and an annular projection part 11 positioned on an inward side of the joint pipe P8 from this flange part 10 (close to the middle in an axial length direction). An O-ring 19 for sealing is mounted in an annular recessed part 14 between the flange part 10 and the annular projection part 11. If both end parts of the joint pipe P8 are fitted into two piping members, for example, the two piping members are connected to each other using the joint pipe P8. In this case, sealing utilizing the O-ring 19 is achieved in a connection location between the two piping members and the joint pipe P8.

FIGS. 14A to 14I illustrate an example of gradual shape change of pipes P until the joint pipe P8(P) is manufactured via pipes P1 to P7(P) from a cylindrical metal pipe P0(P) (unworked pipe).

Here, a pipe expansion part 12 having a stepped part 11 a at one end thereof is formed in the pipes P1 to P3, and as the process proceeds to the pipes P1 to P3, the stepped part 11 a has an angular cross-sectional shape. In the pipes P4 to P6, a part of the pipe expansion part 12 is subjected to pipe contraction treatment, and formation of the annular projection part 11 and treatment for sequentially finishing the formed annular projection part 11 into an angular shape are performed (finishing treatment of the annular projection part 11 is also performed for the pipes P7 and P8). In the pipe P7, a region close to the tip is subjected to slight pipe expansion treatment, and in the pipe P8, the portion subjected to this pipe expansion treatment is formed as the flange part 10. In the pipes P7 and P8 as well, treatment for finishing the annular projection part 11 into an angular shape is executed.

In the pipe machining apparatus A, machining of forming the pipes P1 to P8 in stages is performed.

Next, a constitution of the pipe machining apparatus A will be described.

As is properly shown in FIGS. 2 and 3 , the pipe machining apparatus A includes a lower base 2 and an upper frame 3 which is positioned thereabove. The upper frame 3 freely ascends and descends utilizing a driving source of a motor, a reciprocating cylinder, or the like (not illustrated). Ascent and descent of the upper frame 3 are guided using a plurality of columnar guides 20 provided in a manner of standing upright in the lower base 2.

The pipe machining apparatus A includes a clamping device C which can clamp a plurality of pipes P, a plurality of pipe machining parts S (S1 to S8) which can perform machining of the end parts (both end parts) of the plurality of pipes P utilizing a plurality of machining tools 4, and a transfer device 5 which can transfer the plurality of pipes P through a predetermined path.

The clamping device C includes a plurality of lower clamper parts 6 which is provided on the lower base 2, and a plurality of upper clamper parts 7 which is attached to the upper frame 3 and able to ascend and descend above the lower clamper parts 6.

As illustrated in FIG. 1 , the plurality of lower clamper parts 6 is provided side by side in two left and right rows L and R with a gap therebetween in a horizontal direction. In the present embodiment, each of the rows L and R of the lower clamper parts 6 is constituted to include three lower clamper parts 6. However, the disclosure is not limited thereto. The number of lower clamper parts 6 may be set to one by integrating all of the lower clamper parts 6. In addition, a constitution including more lower clamper parts 6 may be adopted by further miniaturizing the lower clamper parts 6 than those of the present embodiment.

A plurality of recessed parts 60 upward openings into which the end parts of the pipes P are fitted and which have a substantially semicircular shape in a side view is provided in upper surface parts of the respective lower clamper parts 6 (also refer to FIG. 4 ). The pipes P are placed and supported on the lower clamper parts 6 in a state in which both end parts thereof are respectively fitted into recessed parts 60 and cross-linked between the lower clamper parts 6 in the two rows L and R.

The plurality of upper clamper parts 7 is provided in disposition corresponding to the plurality of lower clamper parts 6. Recessed parts 70 downward openings which face the recessed parts 60 of the lower clamper parts 6 and have a substantially semicircular shape in a side view are provided in lower surface parts of the respective upper clamper parts 7. The recessed parts 70 are portions into which upper half parts of the end parts of the pipes P are fitted when the upper clamper parts 7 descend and the end parts of the pipes P are clamped between the upper clamper parts 7 and the lower clamper parts 6. The upper clamper parts 7 and the lower clamper parts 6 are parts which also play a role as dies forming a pair with the machining tools 4 during machining of the end parts of the pipes P, and recessed step parts 60 a and 70 a (which will be described below) are formed in formation locations of the recessed parts 60 and 70.

As means for enhancing removability of the pipes P after machining of the pipes P ends, first and second movable clamper parts 61 and 62 (which will be described below) are also provided in the lower clamper parts 6.

As illustrated in FIGS. 5A to 5C, the transfer device 5 is a device in which a plurality of support parts 50 for supporting the plurality of pipes P can ascend and descend and horizontally move. During an ordinary time, as illustrated in FIG. 5A, the plurality of support parts 50 is positioned at a height lower than the plurality of pipes P to avoid interference with the plurality of pipes P supported on the lower clamper parts 6. When machining of the plurality of pipes P ends, as illustrated in FIG. 5B, the plurality of support parts 50 rises and supports the plurality of pipes P. Thereafter, the plurality of support parts 50 moves in the horizontal direction by a predetermined dimension and then descends. Consequently, each of the plurality of pipes P is transferred to a location corresponding to a next pipe machining part S.

Pipe placement parts Sa and Sb are provided on the lower base 2. The pipe P0 newly input to the pipe placement part Sa from the outside is transferred to a location corresponding to a pipe machining part S1 by the transfer device 5. Meanwhile, the joint pipe P8 which has been machined in a pipe machining part S8 is transferred to the pipe placement part Sb by the transfer device 5 and removed to the outside of the pipe machining apparatus A from this pipe placement part Sb.

The plurality of pipe machining parts S (S1 to S8) is a portion for performing predetermined machining with respect to the end parts of the pipes P using the machining tools 4 such as punches. In the plurality of pipe machining parts S1 to S8, machining for manufacturing each of the pipes P1 to P8 illustrated in FIGS. 14B to 14I is performed. In addition, specific constitutions of the machining tools 4 used in the respective pipe machining parts S1 to S8 differ from each other. However, details of these points will be described below.

The plurality of machining tools 4 freely reciprocates in the horizontal direction in a manner of facing each of both end parts of the plurality of pipes P and can approach and abut both end parts of the plurality of pipes P from both left and right sides thereof. In the present embodiment, as means for causing the plurality of machining tools 4 to freely reciprocate, cam mechanisms, in which ascent/descent cams 36 illustrated in FIGS. 2 and 3 and sliders 26 having the machining tools 4 mounted therein are combined, are employed. The ascent/descent cams 36 and the sliders 26 are provided with inclined surfaces 36 a and 26 a. The ascent/descent cams 36 are attached to the upper frame 3, and when the upper frame 3 descends, the ascent/descent cams 36 descend in response thereto so that the inclined surfaces 36 a and 26 a abut each other. Due to guide operation of the inclined surfaces 36 a and 26 a, the sliders 26 move forward to the side of the pipes P. Rearward movement of the machining tools 4 after machining of the pipes P ends is performed utilizing cylinders 27 for rearward movement, for example, in a state in which the ascent/descent cams 36 have risen. In place thereof, the sliders 26 can also be moved rearward using a return spring or the like.

When the upper frame 3 descends, both the upper clamper parts 7 and the ascent/descent cams 36 descend. However, at this time, first, the upper clamper parts 7 come into contact with the end parts of the pipes P, thereby achieving clamping of the pipes P. Thereafter, the ascent/descent cams 36 descend to positions where they come into contact with the sliders 26, and the sliders 26 and the machining tools 4 move forward toward the pipes P.

FIGS. 6A to 6C illustrate a constitution of the pipe machining part S1. In this pipe machining part S1, the recessed step parts 70 a and 60 a are further provided in the recessed parts 70 and 60 of the upper clamper part 7 and the lower clamper part 6. The machining tool 4 is a punch for pipe expansion. As illustrated in FIG. 6A, in a state in which the pipe P0 is placed on the lower clamper part 6, as illustrated in FIG. 6B, the upper clamper part 7 descends, and the machining tool 4 is press-fitted into the end part of the pipe P. Consequently, the pipe P1(P) having an end part subjected to pipe expansion is manufactured.

Although detailed description of the pipe machining parts S2 to S3 is omitted, the basic constitution thereof is similar to that of the pipe machining part S1.

FIGS. 7 to 9 illustrate a constitution of the pipe machining part S6. In this pipe machining part S6, the pipe P6 is manufactured by performing machining in which the annular projection part 11 of the pipe P5 (machining target) is caused to have a more angular shape. As means therefor, the machining tool 4 has a punch 40 having an expansion/contraction deformation part 42 and a tubular pressing part 41. As illustrated in FIG. 8 , when the punch 40 enters the end part of the pipe P, the outer diameter of the expansion/contraction deformation part 42 increases, and the annular projection part 11 of the pipe P is pressed outward in the radial direction from the inner side of the pipe P. The pressing part 41 presses the annular projection part 11 from the outward side thereof.

The first movable clamper part 61 and a first elastic member 8A are provided in the lower clamper parts 6.

The first movable clamper part 61 is constituted as a part separate from a main body part 63 of the lower clamper part 6 (an example of a different region in the lower clamper part mentioned in the disclosure) and attached to the main body part 63 in a manner of being slidable in the axial length direction of the pipe P. The recessed part 60 and the recessed step part 60 a similar to those illustrated in FIGS. 6A to 6C are provided in this first movable clamper part 61.

In FIGS. 7 to 9 , when the pipe P is clamped by the clamping device C, the annular projection part 11 of the pipe P enters the recessed step part 60 a.

The first movable clamper part 61 includes a first pressure contact part 61 a which comes into pressure contact with the stepped part 11 a on one side of the annular projection part 11 of the pipe P (a stepped part close to the center of the pipe P in the axial length direction) at the time of machining of the pipe P. In the present embodiment, a side wall part of the recessed step part 60 a serves as the first pressure contact part 61 a. Meanwhile, the stepped part 11 a of the annular projection part 11 corresponds to an example of “a first portion of a pipe” mentioned in the disclosure. When the expansion/contraction deformation part 42 expands and presses the annular projection part 11 to the outward side in the radial direction, the first pressure contact part 61 a receives a force Fa from the stepped part 11 a in a first direction D1 (a direction D1 is direction directed toward the inward side from the outward side the axial length direction of the pipe P and is the same direction as the forward movement direction of the machining tool 4) and comes into pressure contact with the stepped part 11 a.

The first elastic member 8A is a coil spring, for example, and corresponds to a specific example of the first displacement member mentioned in the disclosure. This first elastic member 8A elastically biases the first movable clamper part 61 in the first direction D1 at all times. Due to this elastic biasing force, during an ordinary time, as illustrated in FIG. 7 , the first movable clamper part 61 is in a state in which a part thereof protrudes from one side surface of the main body part 63 of the lower clamper part 6 by an appropriate dimension La.

The upper clamper part 7 is provided with a pushing part 78 pushing the first movable clamper part 61 in a second direction D2 (a direction opposite to the first direction DO at the time of machining of the pipe P. This pushing part 78 corresponds to an example of “a first movable clamper part operation part” mentioned in the disclosure. When the upper clamper parts 7 descends, the pushing part 78 descends in response thereto and comes into contact with one side surface of the first movable clamper part 61 as illustrated in FIG. 8 . Consequently, the first movable clamper part 61 is pushed in the second direction D2 against an elastic biasing force of the first elastic member 8A and disposed at the original position.

After machining in the pipe machining part S6 ends and the pipe P6 is manufactured, as illustrated in FIG. 9 , the machining tool 4 moves rearward from the pipe P, and then the upper clamper part 7 rises. Then, the first movable clamper part 61 is displaced in the first direction D1 due to an elastic biasing force of the first elastic member 8A, and the pressure contact state between the first pressure contact part 61 a and the stepped part 11 a of the pipe P is canceled.

The first movable clamper part 61 described above and the constitution related thereto are similar in the pipe machining parts S4 to S8. However, in addition thereto, in the pipe machining parts S7 and S8, as will be described next, the second movable clamper part 62 and means which belongs thereto are further provided.

FIGS. 10 to 12 illustrate a constitution of the pipe machining part S8. In this pipe machining part S8, the annular projection part 11 of the pipe P7 (machining target) is finished into a more angular shape, and machining for providing the flange part 10 is performed. Consequently, the pipe P8 is manufactured. In this case, the machining tool 4 has the punch 40 having the expansion/contraction deformation part 42 and the tubular pressing part 41 having a recessed part 41 a at the tip part.

The lower clamper part 6 is further provided with the second movable clamper part 62 and a second elastic member 8B in addition to the first movable clamper part 61.

The second movable clamper part 62 has a plate shape separate from the main body part 63 of the lower clamper part 6 and the first movable clamper part 61 and is a part positioned between the annular projection part 11 and the flange part 10 of the pipe P and forming the annular recessed part 14 in the pipe P. The second movable clamper part 62 is attached in a manner of facing an outer surface side of the main body part 63 using a screw member 90 such as a bolt. However, this attachment state is a state having slight play in the horizontal direction with respect to the main body part 63.

The second movable clamper part 62 includes a second pressure contact part 62 a which comes into pressure contact with a stepped part 11 b on a side opposite to the stepped part 11 a of the annular projection part 11 of the pipe P at the time of machining of the pipe P. The stepped part 11 b corresponds to an example of “a second portion of a pipe” mentioned in the disclosure. When the expansion/contraction deformation part 42 expands and presses the annular projection part 11 to the outward side in the radial direction, the second pressure contact part 62 a receives a force Fb from the stepped part 11 b in the second direction D2 and comes into pressure contact with the stepped part 11 b. At this time, the first pressure contact part 61 a and the stepped part 11 a also come into pressure contact with each other.

Similar to the first elastic member 8A, the second elastic member 8B is a coil spring, for example, and corresponds to a specific example of a second displacement member mentioned in the disclosure. This second elastic member 8B elastically biases the second movable clamper part 62 in the second direction D2 at all times.

At the time of machining of the pipe P, as illustrated in FIG. 11 , the pressing part 41 of the machining tool 4 presses the second movable clamper part 62 in the first direction D1 and pressurizes it to the main body part 63 of the lower clamper part 6. Consequently, the second movable clamper part 62 can be disposed at the original position suitable for machining so that the annular projection part 11 and the flange part 10 can manufacture an appropriately formed pipe P8.

In addition, at the time of machining of the pipe P, the stepped parts 11 a and 11 b of the annular projection part 11 are in a state of being press-pinched between the first and second pressure contact parts 61 a and 62 a. In contrast, after machining of the pipes P ends, as illustrated in FIG. 12 , the first and second movable clamper parts 61 and 62 are displaced in a direction in which they are separated from the stepped parts 11 a and 11 b due to elastic biasing forces of the first and second elastic members 8A and 8B. Consequently, the state in which the stepped parts 11 a and 11 b of the annular projection part 11 are press-pinched between the first and second pressure contact parts 61 a and 62 a is more appropriately canceled.

The first and second movable clamper parts 61 and 62 described above and the constitution related thereto are also similar in the pipe machining part S7.

According to the pipe machining apparatus A described above, as will be understood from the description with reference to FIGS. 7 to 12 , a situation in which after machining of both end parts of the pipe P ends, the clamping state of the pipe P is canceled by raising the upper clamper part 7 and then a part of the lower clamper part 6 remains while being in strong pressure-contact with a part of the pipe P is appropriately canceled. Therefore, when the pipe P is transferred utilizing the transfer device 5, it is possible to prevent occurrence of a problem of difficulty in detaching the pipe P from the lower clamper part 6 and smoothly transfer the pipe P. As a result, a lead time during machining of a plurality of pipes P can be shortened, and thus productivity of the joint pipe P8 can also be enhanced.

More specifically, as illustrated in FIGS. 7 to 9 , when both end parts of the pipe P are machined into a predetermined shape utilizing the machining tool 4 in a state in which the pipe P is clamped by the clamping device C, the first pressure contact part 61 a of the lower clamper part 6 comes into pressure contact with the stepped part 11 a (first portion) of the pipe P and receives a force in the first direction D1 directed from the outward side toward the inward side in the axial length direction of the pipe P. However, after machining of the pipes P ends, the first movable clamper part 61 including the first pressure contact part 61 a is displaced in the first direction D1 due to operation of the first elastic member 8A (first displacement member). Due to displacement of this first movable clamper part 61, the pressure contact state between the first pressure contact part 61 a and the stepped part 11 a (first portion) is canceled. As a result, a situation in which it is difficult for the pipe P to be removed from the lower clamper part 6 due to a pressure contact force is avoided, and thus the pipe P can be simply detached from the lower clamper part 6 with a light force. Such an effect is preferable in terms of speeding up the work of setting a next new pipe P in the clamping device C and efficiency of enhancing work of sequentially machining a plurality of pipes P.

Moreover, at the time of machining of the pipe P illustrated in FIGS. 10 to 12 , the second pressure contact part 62 a of the lower clamper part 6 comes into pressure contact with the stepped part 11 b (second portion) of the pipe P, and the stepped parts 11 a and 11 b (first and second portions) of the pipe P are in a state of being press-pinched between the first and second pressure contact parts 61 a and 62 a of the lower clamper part 6. In contrast, after machining of the pipe ends, the second movable clamper part 62 including the second pressure contact part 62 a can be displaced in the second direction D2 due to operation of the second elastic member 8B (second displacement member) and can be displaced in a direction in which pressure contact with the stepped part 11 b (second portion) of the pipe P is canceled. In addition, as described above, the first movable clamper part 61 including the first pressure contact part 61 a is displaced in a direction in which pressure contact with the stepped part 11 a (first portion) of the pipe P is canceled due to operation of the first elastic member 8A (first displacement member). Therefore, a state in which the first and second pressure contact parts 61 a and 62 a of the lower clamper part 6 press-pinch the stepped parts 11 a and 11 b of the pipe P is smoothly canceled, and thus workability of removing the pipe P can be made more favorable.

The disclosure is not limited to the details of the embodiment described above. The specific constitution of each part in the pipe machining apparatus according to the disclosure can be subjected to various design change within the intended scope of the disclosure.

In the embodiment described above, the pipe machining apparatus A is constituted to include a plurality of pipe machining parts S and perform machining causing gradual shape change with respect to the plurality of pipes P, but the disclosure is not limited thereto. The pipe machining apparatus according to the disclosure can also be constituted to include only one pipe machining part and can be used for machining one end part in place of being used for machining both end parts of a pipe. Forward movement operation of causing a machining tool to approach a pipe can also be constituted to be performed by a cylinder or the like using a hydraulic pressure or an air pressure, for example, in place of a cam mechanism.

A machining shape of a pipe is also not limited the shapes of the embodiment described above. Therefore, specific kinds and constitutions of a machining tool are also not limited. A shape of a pipe which will become a machining target (a round pipe, an oval pipe, and the like), a size (a caliber, a length, and the like), and a material is also not limited.

The first portion and the second portion of a pipe mentioned in disclosure are also not limited to the stepped parts 11 a and 11 b of the annular projection part 11 of the pipe P and can also be other portions in the pipe P. For this reason, specific shapes, attachment methods, and the like of the first and second movable clamper parts 61 and 62 mentioned in the disclosure can also be variously changed.

It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed embodiments without departing from the scope or spirit of the disclosure. In view of the foregoing, it is intended that the disclosure covers modifications and variations provided that they fall within the scope of the following claims and their equivalents. 

What is claimed is:
 1. A pipe machining apparatus comprising: a clamping device that has a lower clamper part on which a pipe is placed and an upper clamper part which is positioned above the lower clamper part and able to ascend and descend, and is able to clamp an end part of the pipe between the lower clamper part and the upper clamper part; and a pipe machining part that causes a machining tool to abut the end part of the pipe and performs machining of the end part in a state in which the end part of the pipe is clamped by the clamping device, wherein the lower clamper part is provided with a first pressure contact part which comes into pressure contact with a first portion of the pipe at a time of machining of the pipe and receives a force in a first direction from an outward side toward an inward side in an axial length direction of the pipe from the first portion, wherein a region of a part including the first pressure contact part in the lower clamper part is constituted as a first movable clamper part which is separate from different regions of the lower clamper part, and wherein the pipe machining apparatus further comprises a first displacement member that is able to displace the first movable clamper part in the first direction after machining of the pipe ends.
 2. The pipe machining apparatus according to claim 1, wherein the end part of the pipe is provided with an annular projection part having a partially larger outer diameter than other portions of the pipe, wherein the first movable clamper part has a recessed step part where the annular projection part enters when the pipe is clamped by the clamping device, wherein at the time of machining of the pipe, a stepped part close to a center of the pipe in the axial length direction in the annular projection part is constituted to come into pressure contact with a side wall part of the recessed step part, and wherein the stepped part is the first portion, and the side wall part of the recessed step part is the first pressure contact part.
 3. The pipe machining apparatus according to claim 2, wherein the machining tool includes an expansion/contraction deformation part which is able to enter an inner side of the annular projection part and expand the annular projection part at the time of machining of the pipe, and a pressing part which presses the annular projection part in the first direction from the outward side thereof.
 4. The pipe machining apparatus according to claim 2, wherein both end parts including the end part of the pipe and an end part on a side opposite thereto are respectively provided with a pair of annular projection parts as the annular projection part, wherein the lower clamper part has a pair of recessed step parts as the recessed step part where the pair of annular projection parts enter when the pipe is clamped by the clamping device, and wherein at least a pair of pipe machining parts which can cause the machining tool to abut both the end parts of the pipe from lateral sides thereof are provided as the pipe machining part.
 5. The pipe machining apparatus according to claim 1, wherein the first displacement member is a first elastic member which elastically biases the first movable clamper part in the first direction at all times, and wherein the pipe machining apparatus further comprises a first movable clamper part operation part that displaces the first movable clamper part in a second direction opposite to the first direction against an elastic biasing force of the first elastic member such that the first pressure contact part is positioned at a location where the first pressure contact part comes into pressure contact with the first portion at the time of machining of the pipe.
 6. The pipe machining apparatus according to claim 5, wherein the first movable clamper part operation part includes a pushing part which is able to ascend and descend in response to the upper clamper part, and the pushing part is constituted to descend in response to the upper clamper part and abut the first movable clamper part such that the first movable clamper part is pushed in the second direction when the pipe is clamped by the clamping device.
 7. The pipe machining apparatus according to claim 1, wherein the lower clamper part is provided with a second pressure contact part which comes into pressure contact with a second portion positioned on a tip side of the pipe from the first portion in the pipe at the time of machining of the pipe and receives a force in a second direction opposite to the first direction from the second portion, wherein a region of a part including the second pressure contact part in the lower clamper part is constituted as a second movable clamper part which is separate from the different regions of the lower clamper part and the first movable clamper part, and wherein the pipe machining apparatus further comprises a second displacement member that is able to displace the second movable clamper part in the second direction after machining of the pipe ends.
 8. The pipe machining apparatus according to claim 7, wherein the second displacement member is a second elastic member which elastically biases the second movable clamper part in the second direction at all times.
 9. The pipe machining apparatus according to claim 1, wherein there is a plurality of pipes as the pipe, wherein the clamping device is able to clamp the plurality of pipes, wherein a plurality of pipe machining parts is provided as the pipe machining part, and machining in which shapes of end parts of the plurality of pipes are changed in stages by the plurality of pipe machining parts is able to be performed, and wherein the first movable clamper part is provided in a manner of corresponding to at least one pipe machining part of the plurality of pipe machining parts. 